Using the patented Mavis Beacon "Hunt&Peck" Technique, Champ Erm... Look, this is quite probably ill-elephant and all that, but FWIW. When I was playing with the ZZR11, trying for maximum volume on KSBs I experimented with this quite a bit. And, IMHO, there *was* a (quite noticeable) difference between a shut throttle and the kill-switch, at least on that (carbed) bike. So there. -- Wicked Uncle Nigel - Podium Placed Ducati Race Engineer as featured in Performance Bikes and Fast Bikes WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41 SBS#39 OMF#6 Enfield 500 Curry House Racer "The Basmati Rice Burner", Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big" Suzuki TS250 "The Africa Single" Yamaha Vmax Honda ST1100 wiv trailer
Champ said: Not that I'm getting involved in this, but I think an engine with a wide open throttle, but not firing (ignition off or Injection off) will give a greater engine braking effect than an engine with the throttle closed. I base this on nothing more than the vague thought that with a wide open throttle there will be more air drawn into the cylinders which is then compressed by the rising piston. Diesels generally have huge engine braking and (most of them) run on wide open intakes at all times.
Using the patented Mavis Beacon "Hunt&Peck" Technique, Champ Coming from anyone else, I'd have found that quite hurtful. -- Wicked Uncle Nigel - Podium Placed Ducati Race Engineer as featured in Performance Bikes and Fast Bikes WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41 SBS#39 OMF#6 Enfield 500 Curry House Racer "The Basmati Rice Burner", Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big" Suzuki TS250 "The Africa Single" Yamaha Vmax Honda ST1100 wiv trailer
Champ said: So, your thesis is based on closed throttle and no spark? I'd tend to agree with you that any difference between closed throttle and closed throttle with no spark would not be detectable by a normal human backside on the seat. I love you I do.
<reads back through thread> Not in this particular experiment, but the early stages of the debate appeared to concern a 'safety' device which effectively operated a kill switch when it made contact with the ground. Presumably the throttle would be likely to be farly wide open at this point. In that case the deceleration might be more marked than that achieved by snapping the throttle shut. In the specific matter of the Luscher v. Champion debate, as regards the closed throttle over run scenario, your case is convincing. -- +-------------------------------------------------------------+ | Pete Fisher at Home: | | Voxan Roadster Gilera Nordwest Yamaha WR250Z | | Gilera GFR Moto Morini 2C/375 | +-------------------------------------------------------------+
Seems that you have, but there's a nother point you do seem to have completely missed, which is that the 2000rpm range is not in any possible way significant to someone pulling a wheelie. So whether one could notice the change in drive or not is irrelevant - if you've got up to (close to) the balance point you'll be pulling at least something between 8k and 12k rpm, depending on the bike. -- _______ ..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom) \`\ | /`/ GSX-R1000K3 (slightly broken, currently missing) `\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10 `\|/` `
Yes, the question comes down to: does an engine provide noticeably different braking under the two regimes, and does the braking difference vary according to RPM? It clearly does provide noticeably different braking at lower revs, so the only question left is: is this effect noticeable at higher revs? At higher revs on a closed throttle a carbed bike at least will still be burning fuel in its cylinders, though badly, so there must be *some* drive from this. Simple evidence of this burning is the good ol' KSB; if bikes didn't burn the fuel in their cylinders then flicking the killswitch off & on would have no effect.
Certainly IME at lower revs this is not true; I know how the bikes reacted and I know why. It really comes down to whether this effect is noticeable at higher revs, as yourself and others have pointed out. As all my road bikes are FI then I can't try your suggestion ATM because they'll chop the injection when the throttle closes fully, so hitting the K/S would have no effect. <cough> Oh BTW, anyone seen a rattle?
Big singles are very good at KSB. The Nordie would do them occasionally when trying to start it before I sussed the correct plug grade and starting technique. If you opened the throttle while cranking with the starting jet on and it failed to fire, then tried again a most alarming bang would often result. You could also clearly tell the difference in the speed the motor would turn over at starting revs if the throttle(s) (twin CR33s) were open or closed. If the battery was a bit down, opening the throttle would virtually stop it turning over. BTW the best technique in this particular case, unless very cold, is no starter jet and 'catch' it on a whiff of throttle when it fires. This may require a couple of attempts, but can be achieved with a less than 100% charged battery. The starter jet may be required if very cold, but more throttle is needed and a well charged battery to turn it over really smartly. -- +-------------------------------------------------------------+ | Pete Fisher at Home: | | Voxan Roadster Gilera Nordwest Yamaha WR250Z | | Gilera GFR Moto Morini 2C/375 | +-------------------------------------------------------------+
Champ banged the rocks together and said: Whilst the throttle is still closed? I.e. throttle closed Vs. throttle closed and kill switch "killed" With normal cable operated carbs, if you held the throttle open then hit the kill switch air would still be being allowed into the engine. With throttle closed the air would be extremely restricted, hence the intake cycle would create a vaccum, sapping power, causing slightly more decelleration. Maybe. (of course the compression stroke wouldn't have to compress anything much, so that may compensate and result in no difference at all)
If you were to plot the drive from -100 to +100, where -100 is engine off, no fuel, and +100 is engine on, full throttle, I'd reckon that, at higher revs, a closed throttle on a carbed bike would score about -99. I've experimented with this over the years on quite a few bikes and cars I've owned, just out of curiosity to find out whether said vehicles are actually burning any fuel on overrun, and have never been able to notice any difference between closed throttle and kill-swith off on _any_ bike, going back to my XT500 in 1978 all the way through various twins, triples and fours to the current day. -- _______ ..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom) \`\ | /`/ GSX-R1000K3 (slightly broken, currently missing) `\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10 `\|/` `
The Wing will. However, if you open the throttle, the accelerator pumps do their stuff, and Armageddon ensues when the ignition is reconnected - as Uncle Nigel will attest. -- | ___ Salad Dodger |/ \ _/_____\_ GL1500SEV/CBR1100XXX/CBX1000Z |_\_____/_| ..87918../..23274.../..31893. (>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 WG* |__|_|__| BOTAFOT #70 BOTAFOF #09 PM#5 \ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4 \|^|/ ANORAK#17 IbB#4 YTC#4 two#11 '^' RBR Clues: 00 Pts:0000 Miles:0000
Using the patented Mavis Beacon "Hunt&Peck" Technique, SD WHAT? SPEAK UP, I CAN'T HEAR YOU! The green flames were quite impressive, it must be said. They contrast very nicely with the cloud of black smoke. -- Wicked Uncle Nigel - Podium Placed Ducati Race Engineer as featured in Performance Bikes and Fast Bikes WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41 SBS#39 OMF#6 Enfield 500 Curry House Racer "The Basmati Rice Burner", Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big" Suzuki TS250 "The Africa Single" Yamaha Vmax Honda ST1100 wiv trailer
Hmm. Maybe it's a FI only thing, then, though I can't see why that should be so. It was more noticeable in the lower gears. I'm pretty sure the Tuono (or whichever current bike I noticed it on) does it; it seemed pretty consistent, at about say 1500rpm.
I'm not saying you're making it up, just that it may be related only to the specific bike and/or FI system you mentioned. Odd. -- _______ ..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom) \`\ | /`/ GSX-R1000K3 (slightly broken, currently missing) `\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10 `\|/` `
I'm no afficianado of the pouring-ice-cubes-on-the-head scene but I would have though that holding your breath was probably a *good* thing. But this is me so it would probably kill you if you tried. Phil
I've had the bike sideways doing a ksb on a road that was deceptively slippery and when the bike got it's charge of fuel it decided it was time to misbehave. Scared the **** out of me for about 5 seconds.
